Three JavaScript benchmarks show wildly different results

Although Google's latest version of Chrome proved faster than earlier editions in some JavaScript benchmark tests, the browser barely exceeded its predecessors in another, according to Computerworld's tests.

On Tuesday, Google touted a new optimization technology, dubbed "Crankshaft," that it added to Chrome's V8 JavaScript rendering engine, saying that the addition significantly boosted its browser's performance.

Google engineers claimed that Crankshaft raised Chrome's scores in the V8 benchmark by 50%. "This is the biggest performance improvement since we launched Chrome in 2008," said Kevin Millikin and Florian Schneider, in a post to the Chromium blog Tuesday.

V8 is Google's own JavaScript benchmark suite.

Computerworld ran several versions of Chrome three times each through V8 on a Windows Vista PC, then averaged the three scores.

Chrome's "canary" build -- the least stable and most advanced version of the browser -- was 40.5% faster than the "dev" edition and 43.5% faster than the current "stable" version.

Chrome's canary build is marked as version 10, while the dev and stable editions are versions 9 and 8, respectively. The canary edition is the only currently-available version of Chrome that incorporates Crankshaft.

Chrome canary also showed impressive speed improvements over earlier editions in Kraken, the JavaScript benchmark created by rival browser maker Mozilla. According to Kraken, Chrome canary was 55.3% faster at rendering JavaScript than the dev build, and 51.2% faster than the stable edition.

In a third benchmark suite, however, the Crankshaft-equipped canary build proved only marginally faster than other versions of Google's browser. SunSpider scores showed that the canary edition was just 2.2% faster than the dev build and only 3.5% faster than the stable version of Chrome.

SunSpider, created by the WebKit project -- the open-source foundation of both Chrome and Apple's Safari -- is the most widely-cited JavaScript benchmark.

Google's Millikin and Schneider explained the small gains in SunSpider in their blog post Tuesday.

"The idea [in Crankshaft] is to heavily optimize code that is frequently executed and not waste time optimizing code that is not," the two engineers said. "Because of this, benchmarks that finish in just a few milliseconds, such as SunSpider, will show little improvement with Crankshaft. The more work an application does, the bigger the gains will be."

In the V8 tests, Chrome's canary build was over twice as fast as Firefox 4 current beta and Opera Software's Opera 11 preview. When pitted against Microsoft's Internet Explorer 9 (IE9) beta, Chrome was more than five times faster.

Of course, JavaScript benchmarks aren't the only measure of a browser's speed, a fact that Microsoft has repeatedly pointed out even as it's cited SunSpider results IE9.

Last month, Dean Hachamovitch, a Microsoft executive who leads IE development, dismissed browser benchmarks as "at best, not very useful, and at worst, misleading. There's more to real world performance than JavaScript."